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Why You Shouldn’t Trust All Health Advice

Chasing arbitrary health targets can have negative consequences.

Are you chasing arbitrary health targets?
Source: FitNishMedia/Pixabay

If you own a fitness tracker, you may have found yourself pacing the living room late at night to increase your step count and reach that all-so important daily goal of 10,000 steps. And isn’t it satisfying to collect the celebratory Fitbit badge, which congratulates you on hitting the recommended number?

For many health-conscious people, the 10,000 steps target has turned into an obsession. So much so that many people share their personal tips and tricks for reaching the “magical number." For example, have you tried jogging on the spot or parking in the back row of the car park to increase the walking distance to your office? Other discussions focus on technical problems that may prevent people from officially hitting their milestones. Did you know that carrying heavy shopping bags whilewearing your fitness tracker could prevent your arms from swinging and thereby interfere with the step count? Better wear that tracker on your ankle.

Arbitrary numbers

It is a well-known fact that prolonged periods of sitting can compromise overall health and well-being. A sedentary lifestyle may contribute to increased blood pressure, lower lung capacity, and heightened anxiety or fatigue. With this in mind, walking 10,000 steps per day certainly sounds like good advice. However, while plenty of scientific evidence confirms the benefits of being active, no proof exists that 10,000 steps per day is the optimal exercise goal. A number of studies have suggested that people should aim for a weekly minimum of 150 minutes of moderate-intensity aerobic activity, yet the 10,000 steps target fails to take into account the factor of exercise intensity altogether. Overall, it appears to be a completely arbitrary number, which first cropped up in the mid-1960s, when a Japanese company used it to promote their pedometer sales.

However, the 10,000 steps target is only one of many urban health myths that impact on people’s lifestyle choices. Another example is the UK recommendation to eat five portions of fruit and vegetables per day. We all know that fruit and vegetables contain lots of beneficial fibre and vitamins, yet the specific advice of consuming five portions of 80 grams per day lacks any scientific evidence. Indeed, research suggests the higher the vegetable consumption the better, and countries vary in their national guidance on how much to consume for optimal health. Did you know, for example, that Australian guidelines suggest eating seven portions (two portions of fruit and five of vegetables) per day?

Finally, you may have come across the well-known 8×8 guidance, which advises drinking eight glasses of water per day (each containing eight ounces, or roughly 230 millilitres). Again, staying hydrated has many proven benefits. For example, it facilitates kidney functioning and improves the appearance of your skin. However, personal needs of water vary considerably, and daily targets therefore need to be adapted based on people’s exercise levels, the weather in their environment, and their consumption levels of foods with high water content. In extreme cases, downing large quantities of water may even have adverse health effects. Over-hydration can lead to a dangerous reduction of blood sodium levels, possibly with fatal consequences.

The dangers of chasing arbitrary health targets

All of the above health targets lack scientific evidence, yet they ultimately aim to improve people’s health by increasing exercise levels, improving nutrition, and boosting hydration. The simple numeric targets are concrete and easy to remember. They also help people track their progress and stay focused on their aims. So what's the harm in chasing somewhat random numbers on the challenging quest to making healthier lifestyle choices?

  1. Losing sight of the bigger picture. Obsessive pursuit of arbitrary numbers can lead to people to lose sight of the larger, underlying health goals. For example, tricking your child into eating their “5 a day” by smothering strawberries with chocolate or dipping carrot sticks in mayonnaise will hardly result in a healthier diet! Similarly, abstaining from exercise that is unlikely to boost the daily step count (such as yoga or swimming) may limit people’s variety of physical activity and thus be counteractive.
  2. Demotivating numbers. While some people find concrete numbers helpful for personal goal-setting, specific targets can have quite the opposite effect if perceived as unachievable. Fixating on generic health targets may lead to dangerous “all-or-nothing” thinking, demotivating people with lower abilities (or lesser opportunities) and preventing them from making any lifestyle changes at all. In the context of hydration levels, for example, some people may decide against increasing their water intake because they know they’ll never hit the eight-glass target. So what's the point in trying?
  3. Deterring progress. A final problem of following arbitrary health goals is their interference with personal progress. When focusing on a clear, numeric target, people may be tempted to quit their healthy behaviours as soon as they have hit that magic number. A fixation on reaching 10,000 steps, for example, could deter them from striving for more ambitious goals or continuing to exercise when energy levels are high.

Developing a more critical attitude toward common health advice and examining the underlying evidence may be crucial in combatting many unwanted (and unexpected) side effects of supposedly positive lifestyle changes. There is nothing wrong with wanting to boost personal exercise levels, improve food choices, or drink more water. Just beware of chasing arbitrary numbers, which may have quite the opposite effect.

More from Eva M. Krockow Ph.D.
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More from Eva M. Krockow Ph.D.
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